Well you can try newsgroups. There's also some HD bittorrent sites like bit-hdtv.com or Hdbits.net, unfortunately the former isn't accepting new members and the latter is invite only.
I wouldn't know where else to look. Not only am I hoping to find HP1 extended in HD, I'd like to find a better version of HP2 since it seems to have been too low of a bitrate broadcast.